Mac OSX Instruction Update + lipo error "rakneti386.a and raknetppc.a have the same architectures (i386) and can't be in the same fat output file"

[netpoetica]

Using the instructions for building on Mac OSX, this command:

lipo -create *.a -o libraknet.a

produces the following error:

fatal error: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/lipo: rakneti386.a and raknetppc.a have the same architectures (i386) and can't be in the same fat output file

I assume this is likely due to out-of-date instructions, because for example Mac OSX SDK now lives here:

/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.15.sdk

whereas in the README.md file it is listed as /Developer/SDKs/MacOSX10.5u.sdk/. In modern version of Mac OSX, all of the /Developer/SDK stuff lives inside of the Xcode application.